How Priming Exercise Affects Oxygen Uptake Kinetics: From Underpinning Mechanisms to Endurance Performance

Fig. 1. Typical pulmonary oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2) response to a 6-min bout of heavy-intensity exercise. The cardiodynamic phase is followed by the fundamental phase, which is in turn followed by the slow component. The slow component emerges from the fundamental phase some 90–180 s after exercise onset (106 s in this case). Residuals of the fundamental phase fit are displayed at the bottom

Fig. 2. Representative oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2) response to two identical 6-min bouts of heavy exercise, separated by 6 min of cycling at 20 W. Analysis was performed according to the original protocol of Gerbino et al. [1], that is, by fitting a single monoexponential function to the entire \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2 response in each bout. Note the considerable speeding of the overall monoexponential kinetics in bout 2 compared with bout 1, alongside a reduction in the partial oxygen deficit. However, whether this reduction was due to a “true” speeding of the fundamental phase kinetics or to an alteration in the fundamental or slow-phase amplitudes could not be discerned from this study

Fig. 3. Schematic displaying the two different types of priming effect that may occur during two consecutive bouts of heavy exercise. Specifically, prior heavy exercise may cause either a speeding of the fundamental phase kinetics (A), or an increase in the fundamental phase amplitude and concomitant reduction in the slow component amplitude, with no effect on the speed of the kinetics (B). In panel A, the fundamental phase amplitude is identical (2.49 L/min), but the kinetics are faster enabling a more rapid attainment of the steady-state value in bout 2. In panel B, the fundamental phase time constant is the same (τ, 30 s), whereas the amplitude of the fundamental phase is increased and the slow component amplitude is reduced in bout 2. Because the fundamental phase time constant is unaltered in bout 2 in panel (B), this response does not represent a true speeding of the fundamental \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2 kinetics. Both types of response have been…

Fig. 4. Time constant for the fundamental phase of pulmonary oxygen uptake kinetics (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau_{{\dot{V}{\text{O}}_{2} }}$$\end{document}τV˙O2) across 43 priming exercise studies published between 1996 and 2021 with the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau_{{\dot{V}{\text{O}}_{2} }}$$\end{document}τV˙O2 value in bout 2 plotted as a function of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau_{{\dot{V}{\text{O}}_{2} }}$$\end{document}τV˙O2 in bout 1. The values used were limited to studies addressing the effects of prior leg exercise on subsequent leg exercise; however, the intensities of…

Fig. 5. Schematic displaying the characteristic effects of prior heavy exercise on the pulmonary oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2) kinetics and their mechanistic determinants. Green boxes indicate mechanisms with direct experimental support and no clear contradictory evidence. The amber box indicates mechanisms with some experimental evidence both for and against. Red crosses indicate mechanisms that have large amounts of evidence against them. See text for further details

Fig. 6. Two representative subjects showing the effects of priming exercise on pulmonary oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2) responses and the power–duration relationship in situations where priming reduces the fundamental phase time constant (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau_{{\dot{V}{\text{O}}_{2} }}$$\end{document}τV˙O2) is reduced (A–C) versus situations where the fundamental phase amplitude is increased and the slow component is reduced (D–F). In A and D, pulmonary \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O2 responses are displayed in…